The present invention relates to refractory wear parts for use in sliding closure units for metallurgical vessels. More particularly, the present invention relates to such a refractory wear part having therethrough at least one flow-through opening, the wear part being formed of a combination of gas permeable material and gas impervious or impermeable material, with at least one zone formed of the gas permeable material and opening on the surface of the wear part for supplying thereto a gas, for example a flushing, scavenging or other gas for purposes as would be understood by those skilled in the art. This zone, hereinafter referred to as a flushing zone, is connected with an external gas inlet connection by a gas duct. The present invention particularly is directed to a wear plate, such as a stationary or sliding plate having at least one sliding surface.
DE-OS No. 34 06 076 discloses a refractory bottom or stationary plate formed of a main body of refractory gas permeable or porous material and a sliding surface section or zone formed of gas impervious refractory material. A gas chamber is formed within the porous main body around the flow-through opening by means of substances that burn out during firing. After firing, a gas duct is drilled through the plate to connect with the gas chamber, and such gas duct is provided with a gas inlet connection. In order for gas issuing from the gas chamber to reach the flow-through opening through pours in the porous main body, while preventing the gas from escaping through the free surfaces of the main body, such free surfaces are sealed in a gas tight manner by means of a refractory glaze. Due to the unequal strengths of the main body and of the sliding surface section, this known plate is barely capable of satisfactorily withstanding the thermal shock and bending stresses to which the plate is subjected during use. Moreover, the necessity of forming bores in the plate weakens the stability of the plate and increases the cost thereof. The necessity of the provision of the sealing glaze further increases the cost of the plate.